QML UI: make dive list fold dive trips

This makes it MUCH easier to deal with a lot of dives.

Instead of needing a more complicated model we simply use the meta data that
allows us to create the dive trip sections to hide (make invisible + height 0)
all dives that aren't in the selected trip.

I'll admit that this was much easier than I expected it to be.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-mobile/qml/DiveList.qml

@@ -14,12 +14,15 @@ MobileComponents.Page {
 	property int credentialStatus: manager.credentialStatus
 	property int numDives: diveListView.count
 	property color textColor: subsurfaceTheme.diveListTextColor
+	property string activeTrip
 	Component {
 		id: diveDelegate
 		MobileComponents.ListItem {
 			enabled: true
 			checked: diveListView.currentIndex === model.index
 			width: parent.width
+			height: dive.tripMeta == activeTrip ? diveDelegateItem.height : 0
+			visible: dive.tripMeta == activeTrip ? true : false
 
 			property real detailsOpacity : 0
 			property int horizontalPadding: MobileComponents.Units.gridUnit / 2 - MobileComponents.Units.smallSpacing  + 1
@@ -34,6 +37,7 @@ MobileComponents.Page {
 			}
 
 			Item {
+				id: diveDelegateItem
 				width: parent.width - MobileComponents.Units.gridUnit
 				height: childrenRect.height - MobileComponents.Units.smallSpacing
 
@@ -135,6 +139,12 @@ MobileComponents.Page {
 				}
 				color: textColor
 				level: 2
+				MouseArea {
+					anchors.fill: sectionText
+					onClicked: {
+						activeTrip = section
+					}
+				}
 			}
 			Rectangle {
 				height: Math.max(2, MobileComponents.Units.gridUnit / 12) // we want a thicker line